There are many ways to fast. Some people forgo food and water alltogether for a day or two. Some only drink water. Some allow fruit juice or some crazy concoctions (like the Master Cleanse, on which you drink only a mixture of water, maple syrup, blackstrap molasses and cayanne pepper, blegh). Some allow small, bland foods like saltines. You do what you feel is right.
Fasting can help jumpstart a diet but it shouldn't be used as a weightloss plan. It's dangerous if you don't do it right. talk to your doctor about it.
at 2:06 AM on Sep. 10, 2009